48 



tapering, almost bare, and but slightly projecting beyond the latter, terminal 

 joint unguiform. Anterior gnathopoda rather robust, propodos tumid at the 

 base, obpyriform and finely serrated 011 the inferior edge, palmar border not 

 distinctly defined, dactylus short. Posterior gnathopoda very slender and 

 densely hirsute in the outer part, propodos narrow oblong, produced at the 

 tip beneath the rudimentary dactylus so as to form a minute chela. Pereio- 

 poda of nearly uniform size, rather strong, basal joint of the 3 posterior pairs 

 not very much dilated. Uropoda with the rami lanceolate and partly serrated 

 on the edges, last pair slightly reaching beyond the preceding pair, outer 

 ramus the larger and having a distinct terminal joint. Telson comparatively 

 short, deeply cleft. 



Remark*. - This is a very distinct genus, differing, as it does, espe- 

 cially in the structure of the oral parts, very decidedly from the other Lysia- 

 nassidse. Besides the 2 species described below, the Lysianassa ciliata of 

 Heller undoubtedly belongs to this genus, and probably also L. It inn His Costa. 



10. Aristias audouinianus, (,Sp. Bate). 



(PL 17, fig. 2). 



Lysianassa audouiniana, Sp. Bate, Brit. Assoc. Eep. 1855. 

 Syn: Aristias tumidus, Boeck (not Kroyer). 



Body short and robust, with broadly rounded back and sharply defined 

 segments. Cephalon very short, truncated in front, lateral corners almost 

 rectangular and slightly produced at the tip. First pair of coxal plates very 

 small and to a great extent covered by the succeeding pair; the latter only 

 little deeper than the body; 4th pair scarcely broader than 3rd and only 

 very slightly emarginated posteriorly, inferior part narrowly rounded; 5th 

 pair much more broad than deep. Last pair of epimeral plates of meta- 

 some narrowly rounded at the infero-posterior corners, posterior edge smooth. 

 Eyes rounded oval, placed near the lateral corners of the cephalon, pigment 

 black with a whitish coating. Superior antennas about the length of the 

 cephalon and the 3 anterior segments of the mesosome combined, 2nd joint 

 of the peduncle twice as large as the 3rd, and both together about half the 

 length of the 1st joint; nagellum only little longer than the peduncle, 10- 

 articulate, 1st joint rather large; accessory appendage half the length of the 

 fiagellum, 5-articulate. Inferior antennse having the flagellum about as long 

 as the peduncle and 9-articulate. Anterior gnathopoda with the propodos 

 fully as long as the carpus, inferior edge finely serrated and, besides, armed 

 with 4 short spines. Posterior gnathopoda nearly twice as long as the 

 anterior and very slender, propodos about half the length of the carpus, both 



